TrackingWriters, HistoryOf.
"The existence of an area of free land, its continuous recession, and the advance of American settlement westward explain American development."
* FrancisParkman
* TheodoreRoosevelt
* AmericanNationalism
* [http://www.pbs.org/weta/thewest/people/s_z/turner.htm PBS - THE WEST]
http://www.pbs.org/weta/thewest/people/images/turner.jpg